Haven't ridden it but would like to someday. I have read a little about it though. I remember reading that if it's wet, forget it. Hope for dry weather!
Here's a link in case you haven't seen it. The page loads very slowly for some reason, (and I have cable.) http://www.maahdaahhey.com/home.html
If everything seems under control, you're just not going fast enough...
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Yes, I try to ride a little every year. The trail is very good but if it's wet it is not passable. The trail is very isolated so you'll need lots and lots of water. Visit the web site listed in the other post and this one http://www.jwp.bc.ca/westdakota/trails.htm